The invention disclosed herein relates generally to methods for managing resources within a computer system. More particularly, the present invention relates to a system and method for managing resources within a computer system having multiple partitions.
Through logical partitioning, a physical computer system may be divided into two or more logical partitions (“LPARs”), each of which has a share of the physical system's resources and operates as an independent logical computer system within the physical system, having also, for example, its own operating system, user applications, data files, primary language, time of day, etc.
The share of resources allocated to a partition affects the performance of the logical system within that partition, and a lack of one or more resources, such as processor power or memory, may result in performance degradation. Also, since work loads, and consequently, resource needs, may change over time, one defined allocation of resources may not be effective for all situations. Thus, it is advantageous to be able to reallocate resources among partitions to address changes in work loads.
Currently available partitionable systems, such as the AS/400™ systems running the OS/400™ operating system, both from International Business Machines Corporation, support the dynamic reallocation of resources among partitions, e.g., without having to perform an initial program load (“IPL”) afterwards, but do not provide sophisticated tools to execute such reallocations. Generally, dynamic reallocation of resources is performed either at the discretion of a human operator or automatically according to a schedule, e.g., automatically executing a preset resource reallocation based on assumed needs at predetermined times. The first technique is deficient in that it requires a human operator and is time consuming. The second technique, although not requiring an operator after the preset resource reallocations have been defined, has the drawback of reallocating resources based on assumed needs and not on current actual needs of the partitions.
Thus, there is a need for a system and method that automatically determines when partitions suffer performance degradation due to a lack of resources, and dynamically reallocates resources among the partitions to alleviate the identified performance degradation.